Vulkan: No inactive samplers left to cleanup in glslang wrapper

Loose inactive samplers are already removed in
RemoveInactiveInterfaceVariables.  In-struct samplers are always marked
active by CollectVariables if the uniform is active.  If the uniform is
inactive, it is removed entirely by the translator.  Thus no inactive
samplers are left for glslang wrapper to clean up.

Bug: angleproject:3394
Change-Id: Ic0fef052afa992bd612fd22ffa1e5b9aa72a17bc
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1999488
Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>

Author: ShabbyX

src/compiler/translator/TranslatorVulkan.cpp

@@ -730,7 +730,9 @@ bool TranslatorVulkan::translateImpl(TIntermBlock *root,
 
     // Remove declarations of inactive shader interface variables so glslang wrapper doesn't need to
     // replace them.  Note: this is done before extracting samplers from structs, as removing such
-    // inactive samplers is not yet supported.
+    // inactive samplers is not yet supported.  Note also that currently, CollectVariables marks
+    // every field of an active uniform that's of struct type as active, i.e. no extracted sampler
+    // is inactive.
     if (!RemoveInactiveInterfaceVariables(this, root, getUniforms(), getInterfaceBlocks()))
     {
         return false;

src/libANGLE/renderer/glslang_wrapper_utils.cpp

@@ -845,22 +845,14 @@ void AssignUniformBindings(const GlslangSourceOptions &options,
 void AssignResourceBinding(gl::ShaderBitSet activeShaders,
                            const std::string &name,
                            const std::string &bindingString,
-                           bool eraseLayoutIfInactive,
                            gl::ShaderMap<IntermediateShaderSource> *shaderSources)
 {
     for (const gl::ShaderType shaderType : gl::AllShaderTypes())
     {
         IntermediateShaderSource &shaderSource = (*shaderSources)[shaderType];
-        if (!shaderSource.empty())
+        if (activeShaders[shaderType] && !shaderSource.empty())
         {
-            if (activeShaders[shaderType])
-            {
-                shaderSource.insertLayoutSpecifier(name, bindingString);
-            }
-            else if (eraseLayoutIfInactive)
-            {
-                shaderSource.eraseLayoutAndQualifierSpecifiers(name, kInactiveVariableSubstitution);
-            }
+            shaderSource.insertLayoutSpecifier(name, bindingString);
         }
     }
 }
@@ -881,8 +873,7 @@ uint32_t AssignInterfaceBlockBindings(const GlslangSourceOptions &options,
             const std::string bindingString =
                 resourcesDescriptorSet + ", binding = " + Str(bindingIndex++);
 
-            AssignResourceBinding(block.activeShaders(), block.name, bindingString, false,
-                                  shaderSources);
+            AssignResourceBinding(block.activeShaders(), block.name, bindingString, shaderSources);
         }
     }
 
@@ -938,8 +929,7 @@ uint32_t AssignImageBindings(const GlslangSourceOptions &options,
             name = name.substr(0, name.find('['));
         }
 
-        AssignResourceBinding(imageUniform.activeShaders(), name, bindingString, false,
-                              shaderSources);
+        AssignResourceBinding(imageUniform.activeShaders(), name, bindingString, shaderSources);
     }
 
     return bindingIndex;
@@ -998,7 +988,7 @@ void AssignTextureBindings(const GlslangSourceOptions &options,
                                             ? GetMappedSamplerNameOld(samplerUniform.name)
                                             : GlslangGetMappedSamplerName(samplerUniform.name);
 
-        AssignResourceBinding(samplerUniform.activeShaders(), samplerName, bindingString, true,
+        AssignResourceBinding(samplerUniform.activeShaders(), samplerName, bindingString,
                               shaderSources);
     }
 }
@@ -1037,26 +1027,6 @@ void CleanupUnusedEntities(bool useOldRewriteStructSamplers,
             shaderSource.eraseLayoutAndQualifierSpecifiers(varyingName, "");
         }
     }
-
-    // Comment out inactive samplers.  This relies on the fact that the shader compiler outputs
-    // uniforms to a single line.
-    for (const gl::UnusedUniform &unusedUniform : resources.unusedUniforms)
-    {
-        if (!unusedUniform.isSampler)
-        {
-            continue;
-        }
-
-        std::string uniformName = useOldRewriteStructSamplers
-                                      ? GetMappedSamplerNameOld(unusedUniform.name)
-                                      : GlslangGetMappedSamplerName(unusedUniform.name);
-
-        for (IntermediateShaderSource &shaderSource : *shaderSources)
-        {
-            shaderSource.eraseLayoutAndQualifierSpecifiers(uniformName,
-                                                           kInactiveVariableSubstitution);
-        }
-    }
 }
 
 constexpr gl::ShaderMap<EShLanguage> kShLanguageMap = {